220 Royal Society, 



(2.) and (3.) intersect, .\ if# 2 J/2 De the coordinates of point of 



. . ra a,c, + a 3 



intersection, x 9 = y g = m — -. 



a 2 a 3 * 8 a 2 « 3 



Hence the equation to a line through the first point of in- 

 tersection and the focus will be 



y — — — (x— m) — k,(x—m) suppose (4.) 



and the corresponding equation to the line through the se- 

 cond point of intersection and the focus will be 



y = — — -3-=s k 2 (x— m) suppose (5.) 



1 — a 3 a, 2 



7c —k 

 and if $ be the A contained by these lines, tan <J> = ■ l ,£ , 



which by reduction from (4.) and (5.) manifestly becomes 

 "i- g 3 (l+a 2 2 ) 



tan <p 



1 + a^a d+ a 2 2 ) 

 a, — a q 



1 + a^ «3 

 Hence <J> is clearly supplementary to the angle between tan- 

 gents (1.) and (3.), and the circle described about the A 

 formed by the tangents (1.) (2.) (3.) will of course pass through 

 the focus. 



XL. Proceedings of Learned Societies. 



ROYAL SOCIETY. 

 (Continued from p. 55.) 

 May 5, 1842* \ PAPER was also read, entitled, "On Fibre:" 

 (Continued.) -£*• additional observations. By Martin Barry, 

 M.D., F.R.S., Lond. and Ed.f 



On examining coagulating blood, the author finds that it contains 

 discs of two different kinds ; the one comparatively pale ; the other, 

 very red. It is in the latter discs that a filament is formed ; and it 

 is these discs which enter into the formation of the clot ; the former, 

 or the pale discs, being merely entangled in the clot, or else remain- 

 ing in the serum. He thinks that the filament escaped the notice of 

 former observers, from their having directed their attention almost 

 exclusively to the undeveloped discs which remained in the serum, 



* For abstracts of the other papers read on May 5th and 12th, see p. 

 54. — Edit. 



t We are requested by Dr. Barry to add the following as a correction 

 of the fifth paragraph in the above abstract. 



That the corpuscles of the blood are reproduced by means of parent- 

 cells, and by division of their nuclei, he had recorded, not as conjectures, 

 but as observed facts. (See Phil. Trans., 1841, p. 204 and 244, pi. xviii.) 



Dr. Barry's previous observations on Fibre will be found in our last 

 volume, p. 321, 344. — Edit. 



